Détails de la réservation
- Le : 9 June 2017
- De : 14 h 00
- à : 16 h 00
- Salle : Amphi Centre Broca Nouvelle - Aquitaine
Détails de l'évènement
Yoshito Kumagai
Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Japan
"The chemical biology of environmental electrophiles"
Résumé
Included among the many environmental electrophiles are aromatic hydrocarbon quinones formed during combustion of gasoline, crotonaldehyde in tobacco smoke, methylmercury accumulated in fish, cadmium contaminated in rice, and acrylamide in baked foods. Although these reactive species exhibit different chemical structures, the common molecular target is protein nucleophiles. We found that these environmental electrophiles can covalently modify sensor proteins with reactive cysteine residues forming their adducts, resulting in activation of cellular redox signal transduction pathways (PTP1B/EGFR signal, Keap1/Nrf2 pathway, HSP90/HSF1 signal and PTEN/Akt signal) involved in cell survival, cell proliferation, and adaptive response. However, higher concentrations of electrophiles disrupt such signaling by nonselective covalent modification of cellular proteins, leading to cell damage. Persulfide/polysulfides produced by various enzymes appear to capture environmental electrophiles because of the formation of their sulfur adducts without electrophilicity. We therefore speculate that persulfide/polysulfides are candidates for the regulation of redox signal transduction pathways and toxicity during exposure to environmental electrophiles.
Responsable
- Nom : Dominique Rolin